Louvered sheet material



D86. 27, 1949 WARP 2,492,909

LOUVERED SHEET MATERIAL Filed Jan. 11, 1945 Q 5 Sheets-Sheet 1 ,JF I l27 16 INVENTOR.

- I 20 Harald B mM Dec. 27, 1949 H. WARP 2,492,909

LOUVERED SHEET MATERIAL Filed Jan. 11, 1945 3 Sheets-Sheet 2 474 [/3INVENTOR.

yam/d Q 7 9, %m JMW Dec. 27,.1949 H. WARP LOUVERED SHEETMATERIAL FiledJan. 11,1945 s Sheets-Sheet s I INVENTOR. f/(U'OLQ? v UNITED STATESPATENT OFFICE LOUVERED SHEET MATERIAL Harold Warp, Chicago, Ill.,assignor to .Flex-O- Glass, Inc., a corporation of Illinois ApplicationJanuary 11, 1945, Serial No. 572,327 .7 Claims. (Cl. 98-121) Theinvention relates generally to louvered sheet material and, moreparticularly, to louvered sheet material of the general type disclosedand claimed in my U. S. Letters Patent No. 2,366,224, dated January 2,1945.

One object of the invention is to provide louvered sheet material ofimproved construction with the openings in the material small enough toenable the material to be employed as an insect barring screen havingthe added advantage of also intercepting certain direct light rays, moreparticularly, the direct rays of the sun over certain periods of theday.

Another object of the invention is to provide sheet material of thecharacter described which is of a sturdy construction yet composed ofvery thin stock, flexible and capable of being rolled to be suitable foruse as screen, as conveyor belts in certain applications, and for otherpurposes.

Yet another object is to provide louvered sheet material composed ofnarrow elements cut from a solid sheet and turned out of the plane ofthe sheet, in which each element in transverse cross section has anangular shape designed to strengthen the same against bending while notobjectionably reducing the admission of light through the sheet.

Still another object is to provide sheet mate rial, composed of columnsof a plurality of narrow elements cut from a solid, thin sheet andtwisted out of the plane of the sheet, with the strips of the sheetremaining between the columns of elements formed with undulations tostrengthen the sheet and render it more resilient to bending out of theplane of the sheet.

A further object is to provide sheet material, formed by a plurality ofcolumns of elements cut from a solid, thin sheet and twisted out of theplane of the sheet, in which the resultant sheet has a limited andresilient yieldabillty in the direction of the columns giving to thematerial, when employed as a screen, and when properly applied, atautness rendering the material less subject to injury by being capableof absorbing certain shocks to which the material is subjected.

Still a further object is to provide sheet material, formed by aplurality of columns of elements cut from a solid, thin sheet andtwisted out of the plane of the sheet in which the spacing of theelements in their final form may be less than the width of the elements.

Yet a further object is to provide louvered sheet material which isreadily and conveniently patched.

Another object is to provide sheet material, formed by a plurality ofcolumns of narrow, parallel elements cut from a solid, thin sheet andtwisted out of the plane of the sheet, in which the elements ofalternate columns are offset in the direction of the columns.

Yet another objectis to provide sheet material, formed by a plurality ofcolumns of narrow, parallel elements cut from a solid, thin sheet anddivided by narrow strips in which the elements are slightly inclinedfrom a true perpendicular to the dividing strips. 1

Other objects and advantages will become" apparent from the followingdetailed description taken in connection with the accompanying drawings,in which:

Fig. 1 is an elevational view of a piece of sheet material formed inaccordance with this invention. The portion of material shown in Fig. 1is approximately twice actual size.

Fig. 2 is a fragmentary and greatly enlarged view of the material ofFig. 1. Fig. 2 shows the material approximately six times its normalsize.

Fig. 3 is a longitudinal sectional view taken approximately along theline 3-3 of Fig. 2.

Fig. 4 is a longitudinal sectional view taken approximately along theline 4-4 of Fig. 2.

Fig. 5 is a transverse sectional view taken approximately along the line5-5 of Fig. 2.

Fig. 6 is a view similar to Fig. 2 but showing a slightly modified formof louvered material.

Fig. 7 is a longitudinal sectional view taken approximately along theline |--1 of Fig. 6.

Fig. 8 is a longitudinal sectional view taken approximately along theline 88 of Fig. '7.

Fig. 9 is a view similar to Fig. 2 but showing a further slightlymodified form of louvered material.

Fig. 10 is a greatly enlarged view of a portion of the dividing orsupporting strip of Fig. 9.

Fig. 11 is a fragmentary sectional view taken approximately along theline ll-il of Fig. 10.

Fig. 12 is a fragmentary sectional view taken approximately along theline l2--I2 of Fig. 10.

Fig. 13 is a fragmentary sectional view taken approximately along theline |3-l3 of Fig. 10.

Fig. 14 is an elevational view of a sheet of material cut to form amodified form of louvered material but before twisting of the elements.

Fig. 15 is an elevational view of the material of Fig. 14 with thelouvers twisted.

Shown in the drawings and hereinafter described for purposes ofdisclosure are a number of modified forms of the invention: It iscontemplated, however, that still other modifications and variations ofthe invention may be made. It is not intended, therefore, that theinvention is to be limited to the specific forms disclosed. On thecontrary, it is intended to cover all modifications and alternativeconstructions falling within the spirit and scope of the invention asdefined in the appended claims. 1

The invention contemplates the provision of a perforate sheet materialadaptable primarily for use as insect barring screen for windows orsimilar light admitting openings, but also adaptable for use in avariety of other ways, such as conveyor belts for light-weightmaterials, visors, etc. The material comprises generally a plurality ofnarrow, parallel elements 20 disposed at an angle with the plane of thematerial so as to permit passage of air or light, or both, through thematerial while being capable of intercepting'certain direct light rayswhen properly positioned with respect to a light source. To the end thatthe material may be readily and economically manufactured yet be ofsturdy construction, it is in the main formed as a unitary structurewith the elements 20 die-cut and drawn or formed from a solid sheet 2|.Depending upon the purpose to be served or the use to which the materialis to be put, the sheet from which it is formed may be of metal, ofplastic, or possible even some other material, though metal lends itselfmost readily to formation of the material and thus will permit thematerial when made of metal to be most economically produced.

As best seen in Figs. 1 and 2, the sheet of mate-' rial is first outalong parallel, uniformly spaced lines of equal length to form columnsof the narrow elements 20 severed along their side edges but retainedintegral at their ends with dividing and supporting strips 22. Eachelement 20 is then twisted about its longitudinal center line out of theplane of the sheet to become disposed at an angle with the plane of thesheet, as best seen in Figs. 3 and 5. Inasmuch as the material isintended to find extensive use as screen for windows or the like, theelements 20 are here shown as making an angle something less than aright angle with the plane of the sheet, this having been foundpreferable for maximum admission of light and maximum vision through thematerial, while excluding the direct rays of the sun for the vitalportion of the day. It is to be understood, however, that this is anarbitrary angle which might be varied to suit the particular 4 which thelouvered material is made should have a certain degree of resiliency sothat they will tend to assume their normal position if not too severelyor sharply bent, and if it is not treated when in bent position with theintent of having it take a permanent set in that position. In the caseof metal, it must be capable of withstanding a slight drawing operationwhich takes place at the ends of the elements when they are twisted outof the plane of the sheet.

With the elements 20 accounting for all of the material in a column,that is, with no material left between elements, the width of theelements 20, it will readily be appreciated, bears a definiterelationship to the number per inch of such elements that may be cutfrom a sheet 2 I. Likewise, with the exceptions hereinafter pointed out,the

width of the elements also bears a relationship to the spacing of theelements when twisted out of the plane of the sheet. Thus by varying thewidth of the elements 20 the mesh of the resulting material may bevaried just as the mesh of conventional, woven screen varies. The meshof the conditions for which the material is to be employed withoutdeparting from the spirit of the invention.

Though the material may, as already stated, be employed in a variety ofways, an important use is as screen for windows, doors and other lightadmitting openings, and the material will, therefore, be describedprimarily in relation to that use. In order that the material, whenemployed as screen, may admit the maximum amount of light, the elements20 should be of a thickness consistent, of course, with obtaining thenecessary structural strength. The sheet 2| from which the material ismade is, therefore, very thin, preferably on the order of Aim of an inchthough, of course, this is an arbitrary dimension and may be departedfrom to a reasonable extent without departing from the spirit of theinvention. This dimension, moreover, is likely to vary somewhatdepending upon whether the material is made of metal, plastic, or someother composition. The sheets from material may thus extend over aconsiderable range, but, inasmuch as the material when employed as ascreen is intended for and in most instances will be employed for thepurpose of barring insects, the range, at least in so far as the minimumnumber of meshes is concerned, will for that reason h e a practicallimitation. Thus twelve meshes 0 elements per inch may well be a limitin one direction, while twenty elements per inch, due to physicaldifficulties in forming the elements 2|! may be a limit in the oppositedirection.

In Fig. 1, which illustrates the material in approximately twice itsactual size, the elements 2. are, by way of example, shown as runningsixteen to the inch, that is, of an inch in width, while the dividingand supporting strips 22 are shown spaced one inch from center to centerthereof and are of an inch in width. It is to be appreciated that thesedimensions again are all arbitrary, though preferred dimensions,inasmuch as sixteen mesh screen constitutes by far the major portion ofthe screen customarily employed,

and any one or more the width of the supporting strips 22, the width ofthe elements 20, or the spacing of the supporting strips 22, may bevaried. As shown in Fig. 1, the material is formed along eachlongitudinal edge with what is herein referred to as a selvage edge 23.By that is meant simply a marginal portion of the solid sheet varying inwidth from one-quarter to one-half an inch, which is left in its solidor imperforate state. Such a margin, particularly along the longitudinaledges of the material, provides excellent means for the securing of thematerial onto a frame as-by tacking or by clamping be-' tween opposedfaces, and also forms a very excellent guiding portion for traveling inways formed in a window casement or sash where the material is employedas an interior, roll-away screen. It will readily be appreciated thatthe material may, formed as it is of solid sheets and divided intocolumns one inch in width, be made in varying widths in multiples of aninch, and thus will readily be adapted for windows of any size. I

The material, being formed as it is from very thin sheets, is subject toinjury, particularly deformation of the elements 20 by bending at rightangles to the width, thus destroying the parallelism of the elementswith resultant enlargement of the openings through which insects maymore strengthen the elements 20, particularly against such bending, eachof the elements is shaped to have other than a perfectly flatconstruction in transverse cross section so as to gain the inis formedis kept very thin and while the supporting strips 22 are very narrow topermit maximum light and sight through the material.

Where the material is formed from a metal sheet, the reinforcingfilament 21 preferably is a wire. The wire filament is secured to thesupcreased resistance to bending provided by such curved or angularcross section over aperfectly fiat construction. In the form of theinvention shown in Figs. 1 to 5, the elements 20 are given a very slightbend 24 (see Fig. 3) parallel and closely adjacent to an edge thereof soas to result in what for convenience will be termed a lip 25. Theremainder 26 of each element 20 in the form shown in Figs. 1 to 5 issubstantially straight or fiat and this straight portion is disposed atabout .84" with the plane of the sheet measured in the direction ofrotation that the element is twisted.

It is immaterial whether the lip 25 is formed on the right hand edge orthe left hand edge of the elements 26, as viewed in Fig. 3, so long asthe lip projects in the general direction of the element and,particularly, in the same direction away from a perpendicular to theplane of the sheet passing through the center line of the element. Thuswith the lips formed on the right edge of the elements, as viewedin Fig.3, they project downwardly as viewed in that figure, whereas were theyformed as they might be on the left edge of the elements 20, as viewedin Fig. 3, they should project upwardly. It will be apparent that whenso formed the material, even when used as a screen, has no right orwrong side, or no outside or inside. and it is only necessary that carebe exercised that the material be mounted with the elements slopingoutwardly and downwardly. Thus in Fig. 3 the right hand side of thematerial would be considered the outside and, when so mounted, rain ormoisture striking or collecting on the elements 20 would not be trappedbut would be free to run off. Conversely the material of Fig. 3 might beinverted, in which event the lip edge would form the inside of thescreen and, under those conditions, the elements 20 would still have adownward and outward slope and the lips would not serve to hold moistureor tend to direct it inwardly.

Preferably the material is also reinforced in what may be termed itslongitudinal direction, that is, in the direction of the supportingstrips 22. To that end all or selected ones of the supporting strips 22are reinforced by a filament 21 extending longitudinally of the stripsand secured thereto in a manner presently to be described. This filamentshould preferably have substantial tensile strength so as to aid thestrips 22 in giving the necessary tensile strength to the material.Preferably also the filaments 21 should be resilient so as to tend toretain the material in its plane, but must be sufliciently flexible topermit rolling of the material. The filaments 21 may have any crosssectional shape desired but preferably a round filament approximately 9of an inch in diameter is employed. While this diameter of filament maybe departed from, it should preferably not be so large that the filamentof the finished material projects outwardly beyond the edge of theelements 20 when the elements are in their final position. To have thereinforcing filament 21 extend outwardly beyond the edgepf the elements22 has been found to interfere with the rolling of the material. It willbe seen that by employing a reinforcing filament the necessary tensilestrength of the material is obtained while the sheet from which thematerial porting strip 22 by welding either continuously or at closelyspaced intervals, for example, every sixteenth of an inch or multiplesof a sixteenth, so as to coincide with the center lines of the elements22. Such welding at intervals is indicated by the broken line circles 28in Fig. 2. Where the material is formed from plastic, the reinforcingfilament 21 preferably is also of plastic. This filament is then by theapplication of heat or solvent, or both, readily secured to thesupporting strip 22 either continuously or at spaced intervals, the sameas the metal wire. In both the welding of the wire and the securing ofthe plastic filament, especially if they are secured continuouslythroughout their length, there is a tendency, as a result of thesecuring operation, to distort the filament somewhat from its roundcross section to an oval cross section. This resultant oval crosssection of the filaments 21 permits employment of filaments having alarger cross sectional area than a round filament without projectingbeyond the edge of the twisted elements 20 and thus further increasingthe tensile strength of the finished material. It is also pointed outthat in the form of the invention shown in Figs. 1 to 5 the sheet 2| isso held during the die-cutting thereof to form the elements 20 that thesupporting strips 22 remain substantially straight and fiat, as shown inFig. 4. This enables and facilitates the securing of the reinforcingfilament 21 thereto. While the filament 21 has been shown as applied toone side only of the supporting strips 22, it is to be appreciated thatshould still additional strength he desired a similar filament couldlikewise be applied to the other side of the supporting strips 22.

Figs. 6 to 8 disclose a slightly modified form of louvered sheetmaterial. The material is of the same construction as that disclosed inFigs. 1 to 5 save for two respects. Like the material of Figs. 1 to 5,the material of Figs. 6 to 8 is formed from a solid sheet 30 divided bynarrow strips 3| into a plurality of longitudinal columns composed ofnarrow and parallel elements 32 die-cut from the sheet 30 and twistedout of the plane of the sheet. The elements 32, like the elements 20,are curved or bent so as to strengthen the same against bending at rightangles to their width. In this form of the invention each of theelements 32 is given a multiple curvature, this curvature taking theform of a bend 33 formed parallel with and quite closely adjacent toeach edge of the elements 32 so as to form what will for convenience betermed lips 34 and 35. The portion 36 of each element intermediate thebends 33 is kept substantially straight and fiat and is disposed verynearly at right angles to the sheet 30, though preferably the anglethatthis portion 36 of each element forms with the plane of the sheet isshort by at least a few degrees from a true right angle. It is essentialthat the lips 34 and 35 each continue in the general direction of theelement 32 with respect to a perpendicular to the plane of the materialpassing through the center line of the element. In other words, the lipsmust extend in a direction away from such a perpendicular to the planeof the material through the center line of the element. When constructedin this manner, it will be apparent that the material,

even when used as a screen, has no inside or out-.

side, but either side may be turned outwardly so long as the material ismounted so that the elements 32 have a downward and outward slope.

In this form of the invention, the finished material, whether formed ofmetal or ofplastic, is given increased resiliency and to a limitedextent is made resiliently yieldable in a longitudinal direction. Tothat end, the supporting strips 3| (see Figs. 6 and 8) are formed withundulations 31. While these undulations might be formed in a variety ofways, and while they may have varying amplitudes and also varying wavelengths, they are herein formed as an incident to the die-cutting of thesheet 30 to form the elements 32, such formation of the undulationsbeing made possible by the manner in which the sheet 30 is held.Accordingly. the undulations have a wave length correlated with anddetermined by the width of the elements 32 havin a trough or depression38 at the line of severance of the elements and a resulting high pointor crest 33 at each center line of the elements. The result of suchundulations in the supporting strips 3| is, of course, to give thematerial limited stretchability in a longitudinal direction andincreased resiliency of the material, protecting the same againstpermanent injury resulting from the application of force to the face ofthe material when its edges, for example, are held in a frame or thelike. Further, depending upon the amplitude of the undulations and anypossible elongation of the material, the undulations may just compensatefor the elongation maintaining the elements 32 spaced a distance equalto their width, or the undulations may foreshorten the materialresulting in a spacing of the elements by a distance less than theirwidth. Though not shown as being reinforced with filaments extendinglongitudinally of the supporting strips 3|, as is the material in theform of Figs. 1 to 5, it is nevertheless possible that such reinforcingfilaments might be added and secured either to the high spots or crestsof the undulations, or with the filaments also given undulations so asto coincide with the undulations of the strips 3| and then securedcontinuously, as described for the other form of the invention.

Figs. 9 to 13 disclose still a further slightly modified form oflouvered sheet material. In this form the material is still formed froma solid sheet 40 divided by supporting strips 4| into a plurality ofcolumns each composed of narrow and parallel elements 42. These elementsmay have a transverse cross section such as the elements 20 of Figs. 1to 5 or the double curvature of the elements 32 of Figs. 6 to 8. Thefeature of this form of louvered material is that the elements 42 ofadjacent columns are offset longitudinally with respect to each other.Preferably this offset is by one-half the width of an element therebybringing the line of severance of the elements in one column incoincidence with the center line of the elements of the adjacent column.Among other advantages, such a construction has the advantage that anyaccidental extension of the severing cut as an incident to elements thetwisting of the elements will not weaken the supportin strip to anymaterial extent, because each severance cut terminates opposite thecenter of an element in the adjacent column and hence opposite asubstantial amount of material. This is in contrast with a constructionsuch as shown in Fig. 6, wherein the severance cuts in 8 adjacentcolumns are in registry with one another and thus very definitely leaveat those points a supporting strip of only {I of an inch in width.Should one of the severance cuts extend into the strip as a result oftwisting of the elements, the effectiveness of the strip would be.

greatly reduced and it is even conceivable that, should the severancecut on the opposite side of the strip also be extended, the two mightmeet and completely sever the supporting strip.

This offset or staggered relationship of the in adjacent columnsmaterially strengthens the supporting strips .from the standpoint oftensile strength and renders less necessary any reinforcing filaments,though these may here again be applied as described in connection withthe form of the invention shown in Figs. 1 to 5. Like the form of theinvention of Figs. 6 to 8, however, the supporting strips 4| may also begiven undulations so as to increase in well known manner the resiliencyof the material when displaced out of the plane of the sheet, to stiffenthe material somewhat and give thereto limited stretchability in alongitudinal direction. In this form of the inven-- tion, theundulations are complex rather than simple, as in Fig. 8, and can bestbe depicted and visualized as consisting of two waves side by side butdisplaced or half a wave length and, of course, partially merged bylateral overlapping, as must be the case where they are formed in oneand the same strip 4|. As best seen from Figs. 10 to 13, inclusive,there is formed in the supporting strip 4| at the terminus of eachseverance cut a low point 43, depicted in Fig. 10 by small circles.Approximately at the center line of each element 42 is a high point 44again depicted in Fig. 10 by a small circle. Appreciate that thedepressions and high points 43 and 44, respectively, are not sharplydefined but are gradual and that the circles shown'in Fig. 10 areprovided merely to locate the approximate bottom of the low points andthe approximate top of the high points. With the gradual conformation ofthe strips 4| to provide both the low and the high points there will, ofcourse, be a tendency of the low points to merge and, likewise, atendency for the high points to merge, with the result that there isformed a zig-zag ridge or rib composed of the high points and theirtendency to merge, and a corresponding zig-zag valley or trough composedof the low points, the crossing of the ridge and the valley resulting ina point which lies approximately in the original plane of the strip.

The amplitude of the undulations may vary and, depending upon themagnitude of such undulations, the spacing of the elements 42 may beefifected. When the undulations are kept small, they can be presentwithout changing the spacing of the elements 42 by a compensatingelongation of the strips 4| as an incident to the formation of theelements 42. It is believed possible, however, that the undulations maybe given such amplitude as to effect a shortening of the strips 4|, inwhich event the elements 42 of the finished product will be spaced by adistance less than their width giving, in effect, a finer mesh materialwhich will be more efifective to prevent the passage of insectstherethrough and also more effective in prohibiting passage of directlight rays. The undulations, of course, give to the material a limitedyieldability, particularly in a longitudinal direction, and also give tothe material a certain sprlnginess and particularly a resiliency tendingto restore the material to lying in a plane should it be bent out of theplane.

Figs. 14 and 15 disclose a form of louvered sheet material of the samegeneral character as that heretofore described, namely, as composed ofcolumns of parallel elements 45 formed from a solid piece of materialwith the columns separated by dividing and supporting strips 46extending longitudinally of the material. In the forms of the louveredmaterial heretofore disclosed, the angular relationship of the louveredelements with respect to the supporting strips has not been specificallydefined, but the elements have been shown as disposed at right angles tothe supporting strips. In Figs. 14 and 15, the elements 45 are shown asdeparting slightly from a strict right angular relationship to thesupporting strips 46. The inclination of the elements 45 with respect tothe strips 46 may be varied, but herein is shown as departing but a fewdegrees from a strict right angular relationship, more specifically,such inclination that one end of each element 45 is offsetlongitudinally with respect to its other end approximately the width ofan element, that is, of an inch. T he purpose of this inclination of theelements is to permit making of the severing cuts I! as a shearingoperation, that is, by a progressive cut longitudinally of the elementsrather than as a simultaneous cut of the entire length which places anextra load upon the means forming the severing cuts. Whether theinclination of the elements in adjacent columns is in the same direct onas shown in Figs. 14 and 15, or is in opposite directions, is alsoimmaterial. The elements 5 may be shaped as shown in Fig. 3 or as shownin Fig. 7, and the supporting strips 46 may be strai ht and reinforcedor may be formed with undulations, as in Fig. 8 or Fig. 9. and thesevering c ts may terminate directly opposite the severing cuts of theadjacent column. as in Figs. 1 and 6, or may terminate opposite theapproximate midpoint of the elements of the adjacent column, as in Fig.9.

When the material is made from a metal sheet, the surface of thelouvered elements which is upwardly disposed, when the material is emploed particularly as a screen. is preferably treated so that it will atleast diffuse the li ht ra s and preferably so that it will be lightabsorntive. In any event, the surface should not be hi hly polished soas to act as a light ray rei ectin surface. Where the metal is such asto deteriorate rapidly when exposed to the elements,

it is also preferable that some protective coating be given to thematerial. This might, of course, take the form ofpaint, but preferablytakes the form of a galvanizing either deposited electrolytically or bythe older and more conventional hot bath dipping process. Suchgalvanizing, especially the dipping process, not only serves to coat andthereby protect the material against the elements, but the galvanizingmaterial tends to strengthen the supporting strips by building up to agreater than average depth at the points of the severing cuts. When thematerial is formed of a *plastic sheet, the sheet must, of course, betreated so as to prevent the passage of the direct light raystherethrough if the material is to fulfill its function of interceptingsuch direct light rays. This, of course, might be done bythe addition ofsome pigment so as to render the entire sheet more or less opaque, or itmight 75 columns being composed only be done by applying an appropriatecoating to the sheet. a

'Contributingb the advantage of this type of material over ccfiventionalscreen when the material is employed as screen, and similarlyadvantageous when employed in a variety of other ways, such as forconveyors, is the facility with which the material may be repaired whensome one or more of the louvered elements become broken. It is believedreadily understood that to repair a broken portion of this material itis only necessary that thebroken or damaged portion be cut out and thata section slightly larger than the cut-out portion be placed in positionover the broken or damaged portion. It will be found that the elementsof the repair section and the elements of the material being repairedwill readily lie one beneath the other and that the supporting stripswill also lie one against the other where they overlap and are free todo so. The margin formed by the overlap may be secured by spot welding,the supporting strips being welded to one another and the louveredelements being welded to one another.

It is believed apparent from the foregoing that I have perfected alouvered material of greatly improved construction, particularlyimproved in such respects that, though the sheet from which the materialis formed may be extremely thin, yet the material as a whole and theindividual louver elements are strengthened and reinforced in a varietyof ways renderin the material more suitable for use as screen andadditionally suitable for a great variety of other uses, such asconveyor belts for light-weight material, visors, glare shields, etc. Inaddition to strengthening and reinforcing the material and the elementsthereof, I have given to the material increased resiliency and apossible limited yieldability. In addition the louvered ma-, terial,when made as herein disclosed, can, depending upon the magnitude ofcertain dimensions, have any elongation of the supporting strips as anincident to the formation of the material just compensated for so as tomaintain the spacing of the elements by the width of the elements, orthere may be an over-compensation resulting, in effect, in a finer meshscreen. 1 he material has various other advantages as brought out above.Q

I claim as my invention:

1. An insect screen formed from a solid, thin sheet having a pluralityof parallel, continuous and equally spaced supporting strips dividingthe sheet into columns and each of the columns being composed only of aplurality of uniform and parallel elements extending between saidsupporting strips and supported only by integral formation of thesupporting strips and the elements at their ends, each of said elementsbeing twisted about its longitudinal center line at an angle to theplane of the sheet and said supporting strips being formed with a row ofundulations extending longitudinally thereof with the amplitude of theundulations at right angles to the plane of the sheet and with theirperiod corresponding to the spacing of the elements to incorporate inthe screen limited yieldability in the direction of the length of saidsupporting strips.

2. A louvered material formed from a solid, thin sheet having aplurality of parallel, continuous and equally spaced supporting stripsdividing the sheet into columns and each of the of a plurality ofuniform and parallel elements extending between said supporting stripsand supported only by integral formation of the supporting ;strips andthe elements at their ends, each of said elements being twisted aboutits longitudinal center line at an angle to the plane of the sheet andsaid supporting strips being formed with undulations whose amplitude isat right angles to the plane of the sheet and whose periodicitycorresponds to the elements providing a high point and a low point foreach element to incorporate in the material limited yieldabllity in thedirection of the length of said supporting strips.

3. A louvered material formed from a solid, thin sheet having aplurality of parallel, continuous and equallyspaced supporting stripsdividing the sheetinto columns and each of the columns being composedonly of a plurality of uniform and parallel elements having a widthsubstantially greater than their thickness and extending between saidsupporting strips andsupported only by integral formation of thesupporting strips and the elements at the ends of the elements, each ofsaid elements being twisted about its longitudinal center line at anangle to the plane of the sheet, and said supporting strips beingforeshortenedv by displacement alternately in opposite directions out ofthe plane of the sheet, after severance of said elements along theirside edges, to space said elements from one another a distance less thanthe width of said elements.

4. A louvered material formed from a solid, thin sheet having aplurality of parallel, continuous and equally spaced supporting stripsdividing the sheet into columns and each of the columns being composedonly of a plurality of uniform and parallel elements extending betweensaid supporting strips and supported only by integral formation of thesupporting strips and the elements at their ends, each of said elementsbeing twisted about its longitudinal center line at an angle to theplane of the sheet and the elements of alternate columns being offsetlongitudinally of the supporting strips by less than the width of anelement, and undulations formed in said supporting strips to addresiliency thereto.

5. A louvered material formed from a solid,

thin sheet havingya plurality of parallel, continuous and equally spacedsupporting strips dividing the sheet into columns and each of thecolumns being composed only of a plurality of uniform and parallelelements extending between said supporting strips and supported only byintegral formation of the supporting strips and the elements at theirends, each of said elements being twisted about its longitudinal centerline at an angle to the plane of the sheet and the elements of alternatecolumns being offset longi- 12 tudinally of the material by one-half thewidth of an element, each of said supporting strips being formed with adouble series of undulations.

6. A screen-like material formed from a solid, thin sheet having aplurality of parallel, continuous and equally spaced supporting stripsdividing the sheet into columns and each of the columns being composedonly of a plurality of uniform and parallel elements extending betweensaid supporting strips and supported only by integral formation of thesupporting strips and the elements at the ends of the elements, each ofsaid elements being twisted about its longi tudinal center line at anangle to the plane of the sheet, and each element, in the direction ofthe length thereof, forming with the supporting strips to which it isattached an angle deviating by a few degrees from a right angle.

7. An insect screen formed from a solid, thin sheet having a pluralityof parallel, continuous and equally spaced supporting strips dividingthe sheet into columns and each of the columns being composed only of aplurality of uniform and parallel elements extending between saidsupporting strips and supported only by integral formation of thesupporting strips and the elements at the ends of the elements, each ofsaid elements being twisted about its longitudinal center line at anangle to the plane of the sheet and composed of a major central portiondisposed at a large angle to the plane of the sheet and a minor flangeat each edge, each flange forming a small angle with the major portionand extending in the same general direction away from the major portionas that half of the major portion carrying the flange extends from aperpendicular to the sheet passing through the center line of theelement.

- HAROLD WARP.

assurances crran The following references are of record in the file ofthis patent:

